That's a very sad thing and it again shows that lack of forgiveness in the Puritan society of 16th century. Pearl thus stands for innocence in the novel- innocence that is tainted by someone else's sins. Dimmesdale represents the psychological damage that wrong teachings of the Church could produce. He is also symbolizing the weakness in the structure of the Church. He is a minister who preaches people against adultery but has committed a sin himself. He is a human being and if seen with compassion, he should be allowed to have a family but the Church sees him as a sinner and the constant pain and anguish that he undergoes leads to serious psychological damage. He is so upset with the Church that he proclaims: "Were I an atheist...I might have found peace, long ere now" (1499

Chillingworth is the husband who went missing for few years during which Hester gave birth to Pearl. He represents anger and hostility the society shows against a sinner. He wants to avenge what he sees as betrayal. He stands as a symbol of fake morality and ethics. He is a doctor by profession and is supposed to provide care and compassion to people. But he is only making others lives more difficult by reminding them of their sins. He causes immense pain to Hester and Dimmesdale since he knows about their connection....

The darkness of his soul is obvious when he meets Hester to reveal his identity even though he tries to mask "this expression with a smile; but the latter played him false, and flickered over his visage so derisively that the spectator could see his blackness all the better for it" (1397).
In short the whole novel is allegorical but not in the same way as some critics have felt. Instead in a realistic manner, the novel uses allegory to highlight the lack of compassion in Puritan society. He describes the society as "the bearded men, in sad-colored garments and gray, steeple-crowned hats" (1331). Thus the whole novel is about Puritan society and the Church where they are attacked for their false teachings, wrong ideals, and lack of compassion.

References

Hawthorne, Nathaniel. The Scarlet Letter. The Norton Anthology of American Literature, Fifth Edition. W.W. Nina Baym, Editor. Norton & Co. New York, N.Y. 1998.

Winters, Y. Maule's Curse: Seven Studies in American Obscurantism. New York: New Directions, 1938

FO Matthiessen. American Renaissance: Art and Expression in the Age of Emerson and Whitman (Galaxy Books): 1941

Richard, Chase. The American Novel and Its Tradition: The Johns Hopkins University Press; New Ed edition (May 1, 1980)